Process for breaking petroleum emulsions



Patented July 1, 1952 I PRQCESS' FOR BREAKING PETROL EUM' 1 .7 1 H ,y EMULSIONS ;-Me1vin he Groote, University City, Mo assignor v a w-PetroliteC0171)oration, Ltd., Wilmington, Dela 9 acorporationof'Delaware I No DrztwingLApplication Septeniber25i1950, I I I SerialNo. 186,684

' My invention provides ban "economical and rapid process for" resolving "petroleum emulsions of the water-in-oiftype that are commonly referred to as 'cut 011; "roilyoil," emulsified 'oil', etc., and which comprise fine droplets of naturally-occurring waters or brines dispersed'in a more or less permanent state'throughout the oil which constitutes the continuousphase -of the emulsion. It alsoprovidesan economical and rapid process for "separating emulsions which have been prepared under controlled conditions from mineral oil; such as crude-oil and relatively soft waters "or weak brines; Controlled emulsification and subsequent demulsification under the conditions just mentioned are of significant value in removing impurities, particularly inorganic salts, from pipeline oil."

Demulsification as contemplated in the present application includes thepreventive step of commingling the demulsifier with the aqueous component which would or might' subsequently become either phase ,of the emulsion in the absence of such precautionary measure. Similarly, such demulsifier may be mixed with the hydrocarbon component. I g

The demulsifying agent employed in the present-process is ai'ractional ester of a tetraba'sicacidin"which threecarboxyl radicals appearj in' ester form and a sulfo radical appears salt from; Such "compounds can be derived from-yarious tricarb'oi y acids bysulfonation but for' the herein specifled;purpose are limited to those de'rived'ffrom aconitic acid: -;Such compounds thenare derived/by "reaction involving threetypes of reagents; (n'-)*p.o1ypropylene glycol 01 a molecular weight-sufficient to give waterinsolubility' and kerosene=solubility,- generally being' re the molecular'weightrange of 750 to approximately 3,800: ,(b)' acon'itic acid, and ('c) analka'li metal "bisulfite such as sodium bisulfi'te or-potassium-bisu1fite. x The-preparation oi the demulsifying iagent involves substantially two steps: (a) Esterification} between threemolesfof the polypropylene glycol and one 'moletoiaconitic acid, and '(b) alkali metal bisulfite such asisodium bisulfite.

More=specifically then the mresent invention is concerned'with aprdcess -for *breaking petrolof a demulsifier ineluding hydrophile "synthetic reaction ofsuch fractional ester with a suitable G GlaimS. (01. 253-335) products; said hydrophile --syntheti'c-' products" being characterized by the following "formula:

in which v a whole number varying irom 10-to"80, with the ,proviso' that the polypropylene 5glyco1 prior to esterification 'be' 7 water insolubleljand kerosene:

soluble. v i I In the above formula the man metal cation is shown as sodium whichI is the cheapest'and most readily available. -*Needl 'o'ther alkali metal cation, su' potassium; may vbe employed ln'thefor otassium' bjsul fiteiand'isjincludedjin tne h'eret ttac eu claims as "the obvious chemical equ'i lent. 'fSimi'Iarl-y ammonium bisulfite mayfbe employed instead o'f sodium or potassium j bi sull-ite; :This applies also to a 'bi'sulfite 'of vario, 'rg anic iba'ses provided,

Hg? suifite are as basic asammonia "and-that the sulfite is water-soluble; j these are the "ob; vious functional 'eqliiyaleiits'"oi.isodium bisuliite. The procedure is ,illustrated by the following 40 example:

with a;'pproxinra teIly 1 r em I In this instanc' mme f r r also added-'- 5Q- c; and refluxing-permit I hours. The m'airimumf temp' reflux period-was 1 20 p, which distilled oyer w At the end of the reaction there was still a slight acidity due to possibly uncombined aconitic acid and unquestionably due either entirely or in part to the presence of the acid catalyst. A small amount of 30% aqueous caustic soda was added until sufi'icient had been introduced to neutralize the free acid radicals. After this adjustment 6 grams of powdered sodium bisulfite were "added; Apparently enough water had been added along with the caustic soda to dissolve at least part of the sodium bisulfite so that further addition of water was not required. Needless to say, if no caustic soda solution was added to neutralize the acidity then a little water of toluene sulfonic acid, approximately 1% oi the weight of the glycol, or slightly less, was used in the esterification step. A larger amount should not be used because there may be decomposition of the glycol. Smaller amounts can be used, for instance, /2% or based on amount of glycol, provided, however, that the esterification time is extended somewhat. i

The products'obtained; are comparable to the initial glycol in appearance, etc., i. e., usually they are an amber color or at least of a slight straw color, and often somewhat thicker than the original glycol. This description, of course,

applies to materials after the removal of the should be added to dissolve at least part or all solvent, i. e., the xy o r use s emulsifiors of the sodium bisulfite so as to give a saturated th r is no need, t r movo t e Xylene a it may solution. The reaction mixture was stirred for remain behind. .0bviously other liquids than three hours. No effort was made to have any Xylene may be used in esteriflcation procedure. reflux take place during this stage of the reaction However, if the boiling point is any higher than for the obvious reason-that if water were removed Xylene there danger t decomposition y and the sodium bisulfite were anhydrous there e .p oe u s t e amou t of Sulfonic acid would be little or no opportunity for reaction. is lodlloodother catalysts Such s a Small This was necessary also for the reason that amount of. dry hydrochloric acid can be used sodium bisulfite beginsto decompose at: about, but it a pears lessfdesirable than the sulfonic 100 0. and this reaction obviously must be conac d- N s to the caustic soda solution ducted at a suitable temperature until the sodium used neutralizes I the sulfonic acid catalyst bisulfite has combined. Thereafter the xylene p can be distilled over in the usual manner, re- T o oi i se n io fio i p o u e moving any water with it and all the xylene can is a 3 ot th k n d i d in Patent be removed by distillation; particularly vacuum 2 9 3 da ed 1 19 0. 0 De' Groote distillation. and Keiser. Any conventional equipment can The same procedure was followed in connecbe used, eitheron a small scale, 'pilotplantjscale, tion with a number of additional examples, all 01' larger'scale. of which are illustrated in the following table In-the various examples vpreceding only one which gives the reactants, amounts employed, glycol has been used in these cases. Actually temperature of esterification, etc. there s qr w ron y use wo Tablel Amt Amt. ES" Esteriflca- 15 5c??- Rgam" Used. Acid Reactant Used 3 ,i, %g? tion time fiig tion 53 (are) (a LA; 0 (gm) Tgi lp (hm) AconiticAcid 9.3 so 120 3 -6 80-96 p, -.do 9.3 v127 4, a 80-95; a 9.3 45 130 4 6 80-95 9.3 -132 r 3% 6 80:95 i

,YQPolypropylene 'glyco'ls are commercially. av aildifferent glycols, for instance, an equimolar mixable.l Such polypropyleneglycolsarefurnished so true of two glyccls, one .for example' having a in-various molecular weight ranges.- "I v water'- molecular weight, or 2000 andthe other 3000; or insoluble, kerosene-soluble polypropylene 'glycols one having a molecular weight of 15 00, and the begin in' 'the'molcular weight range somewhere other 2500 -A ctual1y these-gly ls are cogeneric above 500 and more'lspecifically at about 700 or mixtures at .eacl f selected' olecular weight. 750. 'The molecularlweight' was usually deter- 55 Since aconiticacid hasth ree arbo'xyl'si'one ooum mined by the hydroxyl method. Such hydroxyl select glycols of threl e different molecular weights, molecular weight is ajiraction, sometimes a large p for instance, 1: 5 00, 22"5.0,and 3000.. -Momentarily, majorjfr'action, of the theoretical molecular one need only loo valisirnple(situation. i. e., weight based on the method of synthesis; i. e., if maleic acid wer d 5;, a' compound the calculated molecular weight'based theoretihavin two carboxylradicals. :1 'tead of -three, many on the value one would expect to obtain In such event ifone does more a mixture of the by treating water or propylene glycol, for ex-. kind heredescribed actually ithre typ'es o'ircomample, with propylene oxide. Needless to say, pounds will appear, one type nQ v'Vhieh both one does not obtain a single compound but a carboxyrradicalsof the dicarb acidare joined propylene glycol of a molecular weight or .750 or with thehig'h'er.glyeoLL one type wher..pqt1if 1,000 or 2,000. as the.case 'may be, and which really represents a.-, cogeneric mixture whose statistical average molecular weight is the one indicated, Reference in .the'table of course, to -hydroxyl value molecular weight for" the obvious reason that this is'the basis for calculating the amount-of reactants req i f dg 3 I In all instances a small amount of 30% caustic soda solution wasused as in the more complete description of Example 1; and also an amount b xyl are joinedwith here one carbcxyl united col and. the other es e m I as r d i one used three different, rps b mren i qi .crease. There. ,no

h mor oboe-111.111?

. -clva ita e J nyusl e sumv mixture but it can be done if one cares to do so; 7

access:

cThe products .sdzobtained are .peculiar insofar, that (a) there is not present any radical having, 8or'-:more uninterrupted carbonatomaand .(b)

the compounds, are not :particularly effective as,

surface-active agents-in theyordinary sense :due

eitherto the largemolecular size or, the :absence, of a hydrophobe. radical ofrz-t-he kind-previously referred to, or ron-some'othiert reason which is obscure. The chemical compounds herein employed as demulsifiers have molecular weights varying from more 'than 1500 up to several thousands, for instance, 6.000, 7500 and 9000, and yet contain only one su'lfo radical. Utility of such compounds for industrial uses is rather unusual. They are not effective emulsifying agents, but are valuable as-anadditive or a promoter of emulsions. These compounds also have hydrotropic propert and serve as common solvents in the preparation of micellar solutions. It is to be noted that they are free from terminal carboxyl radicals and thus difier from reagents obtained, for example, by treating one mole of a high molal polypropylene glycol with 2 moles of a dicarboxy acid. It is probable these reagents, due to their peculiar structure and their peculiar solubility characteristics; will find utility in other fields of, applicationnow unknown.

Conventional demulsifyingagents employed inv the ztreatment of oil field emulsions are used as such, or after dilution with any suitable solvent, such, as water, petroleum hydrocarbons, such as benzene, toluene, xylene, tar acidoil, cresol, anthracene .oil, etc. Alcohols, particularly aliphatic alcohols, such as methyl alcohol, ethyl alcohol, denaturedalcohol, propyl alcohol, .butyl alcohol, hexyl alcohol, octylalcohoL-etd, may be, employedpas diluentsn Miscellaneous solvents such as pine oil, carbon tetrachloride, sulfur-dioxide; extract obtained in the refining of petroleum, etc., may be employed as diluents.- Similarly, the material or materials employed as the demulsify-ing 'agentio'f my process may be admixed with one or more of the solvents customarily used in-connection with conventional demulsifying agents. .Moreover,,said'material .or materials may be used alone or in admixture with other suitable well-known classes of .demulsifying agents.

It :is well known that conventional demulsitying agentszmay-be used in a water-soluble form, orin an oil-solubleformgor ina form exhibiting bot-ii oiland water-solubility. Sometimes they may be used in a form-which exhibits relatively limited oil-solubility. :I-Iowever, since such reagents are fr equentlyusedina'ratio of 1to'10,000 or l to 20,000, or -1 to =30,000,=or even 1 to 40,000, or '1 to 50,000 as in desalting practice, such an apparent insolubility in oil and water is not significant because said reagents undoubtedly have solubility within such concentrations. This same fact is true in regard to the material or materials employed as the demulsifying agent of my process.

In practicing our process for resolving petroleum emulsions of the water-in-oil type, a treating agent or demulsifying agent of the kind above described is brought into contact with or caused to act upon the emulsion to be treated, in any of the various apparatus now generally used to resolve or break petroleum emulsions with a chemical reagent, the above procedure being used alone or in combination with other demulsifying procedure, such as the electrical dehydration process.

One type of procedure is to accumulate a volume of emulsified oil in a tank and conduct a batch treatment type or ,demulslfication .DI'OCG.

dure to'recoverclean'oil. In this procedure the emulsion is admixed iwiththe :demulsifier, :for example by agitating the, tank 'of emulsion and slowly dripping demulsifier into the emulsion. In some cases mixing is achieved by heating the emulsion while dripping in the demulsifler, depending -upon the =|convection currents in the emulsion to :produce satisfactory admixture. In a third modification of this type of treatment, a circulating pump withdraws-emulsion from,e. g., the bottom of the tank, :and reintroduces it into the :top of the tank, the .demulsifier being added, for example, -:at the suction side of said circulating pump.

In a second type of treating procedure, the demulsi'fieris .introduiced into the well fluids at the well h'ead-orat some point between the well-head and the final zoilstorage Ztank,-by 'means 'of an adjustable :pr'oportioning mechanism or proportioning pump. Ordinarily :the flow :of fluids through the subsequentlines and :fittingszsufiices to produce the desired degree of rmixingkof .demulsifier and emulsion, although .in .some instances additional mixing devices may beintroduced into the flow system. In thisgeneral procedure,-the1system-may include various'mechanical devices for withdrawing free water,.separating entrained water, or accomplishing quiescent settling of the chemicalized emulsion. Heating. devices may likewise be incorporatedin any of the treating procedures describedherein.

'A third type 'of' application (down-the -hole) of'demulsifierto' emulsion is to introduce the demulsi'fier either periodically or'continuously in diluted or undiluted form into the well and 'to allow it to come to the surface with the well fluids, and then to flow the 'chemicalized emulsionthrough any desirable surface equipment, such asemployedfin the other treating procedures. This'parti'cular type of-application is decidedly useful'when .the 'demulsifier is used in connection'w'ith acidification 'of calcareous oilbearing strata, especially if suspended in or dis-- solved in the acid employed for acidification.

, Inall cases, it will beapparent from the "foregoing description, the broad process 'consists'simply in introducing a relatively small proportion of demu'lsi'fier into airelatively large proportion of emulsion, admixing the chemical and emulsion either through natural .fiow or through special apparatus, with or without the application of heat, and allowing the mixture to stand quiescent until the undesirable water content of the emulsion separates and settles'from the mass.

- The ,following is; a typical installation:

A reservoir to hold the demulsifier of the kind described (diluted or undiiuted) is placed at the well-head Where the eiiluent liquids leave the well. This reservoir or container, which may vary from 5 gallons to 50 gallons for convenience, is connected to a proportioning pump which injects the demulsifier drop-wise into the fluids leaving the well. Such chemicalized fluids pass through the fiowline into a settling tank. The settling tank consists of a tank of any convenient size, for instance, one which will hold amounts of fluid produced in 4 to 24 hours (500 barrels to 2000 barrels capacity), and in which there is a perpendicular course of demulsification. The settling tank has two outlets, one'being below the water level to drain ofi the water resulting from demuisification or accompanying the emulsion as free water, the other being an oil outlet at the top to permit the passage of dehydrated oil-to a second tank, being a storage tank, which holds pipeline'or dehydrated oil. If. desired, the conduit or pipe which serves to carry the fluids from the well to the settling tank may include a section of pipe with bafiles to serve as a mixer, to insure thorough distribution of the demulsifier throughout the fluids, or a heater for raising .thetemperature of the fluids to some convenient temperature, for instance, 120 to 160 F., or both heater and mixer. Y

Demulsification procedureris started by simply setting'the pump so as to feed a comparatively large ratio of demulsifier, for instance, 125,000. As soon as acompletebreak? or satisfactory demulsification is obtained, the pump is regulated until experience shows that the amount of demulsifier being added is just sufficient to produce clean or dehydrated 011., The amount being fed at such stage is usually 1:10,000, 1:15,000, 120,000, or the like.

In many instances the products herein specified as demulsifiers can be conveniently used without dilution. However, as previously noted, they may be diluted as desired with any suitable solvent. For instance, by mixing 75 parts by weight of such derivative, for example, the product of Example 1 with. 15 parts by weight of xylene and 10 parts by weight of "isopropyl 'alcohol, an excellent demulsifier is obtained. Selection of the solvent will vary, dpending upon the solubility characteristicsof the product, and of course will be dictated in part by economic considerations, 1. e., cost. 7

As noted above, the products herein described may be used not only in diluted form, but also may be used admixed. with some other chemical demulsifier. A mixture which illustrates such combination is the following:

The derivative, for example, re. product of Ex ample 1, 20%;

A cyclohexylamine salt of a 'polypropylated naphthalene mono-sulfonic acid, 24%; I

An ammonium salt of. a polypropylated naphthalene mono-sulfonic acid,'24%;

A sodium salt of oil-soluble mahogany petroleum sulfonic acid, 12%;

A high-boiling aromatic petroleum solvent,

Isopro'pyl alcohol, The above proportions are all weight percents. Having thus described myinvention, what I claim as new and desire to secure by Letters Paten,is:- "x= 1-. A process for breaking petroleum emulsions of the' water-in-oil' type characterized by subjecting theemulsion to the action of a demulsifier" 1 including hydrophile synthetic products; said 'hydrophile synthetic products being characterized by the following formula:

'owoinmon is the trivalent radical of aconitic acid and n is a whole number'varying from 10 to 80, with the proviso that the corresponding polypropylene glycol of-the formula HO(C3H6O)1|,H be waterinsoluble and kerosene-soluble.

2. The process of claim 1 wherein the value of n is approximately1 5.

-3. The process'of claim 1 wherein the value of n is approximately 25.

v4. The process of-claim 1 wherein the value of n is approximately 35.

5. The process of claim '1 wherein the value of n is approximately 45.

6. The processof claim 1 whereinthe value'of n is approximately 55.

MELVIN DE GROOTE."

' REFERENCES CITED The following references are of record inthe file of this-patenti V V UNITED STATES PATENTS 2,514,399 Kirkpatrick et al. July 11. 1950 

1. A PROCESS FOR BREAKING PETROLEUM EMULSIONS OF THE WATER-IN-OIL TYPE CHARACTERIZED BY SUBJECTING THE EMULSION TO THE ACTION OF A DEMULSIFIER INCLUDING HYDROPHILE SYNTHETIC PRODUCTS; SAID HYDROPHIL SYNTHETIC PRODUCTS BEING CHARACTERIZED BY THE FOLLOWING FORMULA: 